138 MEMOIRS OF THE CARNEGIE MUSEUM 



Arius parkeri Gunther, Catalogue, V, 1864, 153 (copied). 



Galeichthys parkeri Jordan, Proc. U. S. Nat. Mus., IX, 1886, 559 (name only). 



Tachisurus parkeri Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), 1, 1888, 



141 (name only); Occasional Papers Cal. Acad. Sci., I, 1890, 65. 

 Selenaspis parkeri Jordan and Evermann, Bull. U. S. Nat. Mus. No. 47, I, 1896, 



123. 

 Arius guadriscutis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 



111 (Cayenne; Mana).— Kner, SB. Akad. Wiss. Wien, XXVI, 1857, 389 



(Para). 

 Netuma quadriscutis Bleeker, "Silures de Suriname," 1864, 59, pi. 8, pi. 13, fig. 2 



(Surinam). 



Several specimens, 238-408 mm. Georgetown market. (C. M. Cat. No. 

 1272-1279; I. U. Cat. No. 11775.) 



I have also examined the specimen of quadriscutis mentioned by Bleeker. 



Head 3.6; depth 5.33-5.5; D. 1,7; A. 15-18. 



Body comparatively stout, the greatest width equaling the greatest depth. 

 Head large, flatfish above; profile descending; width of head 1.17 in its length; 

 width at the mouth 2-2.4, its depth at the base of the occipital process scarcely 

 less than its greatest width. Top of head coarsely granular in young, the granules 

 becoming finer and more regularly arranged in the adult; opercles smooth; humeral 

 process with radiating lines of granules. Dorsal plate large, emarginate in front, 

 receiving the pointed occipital process. Middle of the fontanel above the posterior 

 margin of the eye. No skinny flap connecting the posterior nostrils. 



Maxillary barbels extending little beyond the base of the pectoral or shorter; 

 mental barbels short. Teeth in jaws coarse, conical, those on the palate and 

 vomer finely granular, the patches separate in the young, but united and covering 

 most of roof of mouth in the adult. Gill-membranes forming a broad marginal 

 flap across the isthmus. Gill-rakers 3^1 + 7-9. 



Distance of dorsal from tip of snout 2.33 in the length; the spine 1.33-1.6 

 in the head, granular in front, serrate behind. Distance of adipose fin from the 

 dorsal 4-4.5 in the length, the adipose fin twice as long as high, adnate, as long 

 as the dorsal fin. 



Caudal forked, the upper lobe longer, 4.33-4.5 in the length. Anal fin about 

 as long as high, 2.15-2.25 in the head. Ventrals 1.75-2 in the head. 



Pectoral spine stout, 1.25-1.16 in the head, granular in front (serrate in young), 

 striate on sides, serrate along inner margin. 



Yellow in life. The most abundant catfish of the Georgetown market. 



